Amazon rainforest is the thickest rainforest that spans over a billion acres. It is also known as Amazonia. The Amazon rainforest touches the borders of nine South American countries. It’s largest portion is in Brazil. Amazonia covers more than half of Brazil. The Amazon rainforest is one of the world's greatest natural resources because its vegetation continuously recycles carbon dioxide into oxygen. It has been described as the "Lungs of our Planet". About 20% of earth's oxygen is produced by the Amazon rainforest. Today, more than 20% of the Amazon rainforest has been destroyed and is gone forever.